This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-251511, filed Sep. 6, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a data recording medium and a data recording method of such a medium, which is a data recording medium on which data is recorded as a code that can be optically read by using a manual scanning process, and which is provided with an non-interference area in which only a non-interference image having an attribute causing no adverse effects on the code reading process is allowed to exist, so that, even when a reading device is not accurately positioned on the code due to the manual scanning process, it is possible to prevent the code reading process from being interrupted by interference from images located on the periphery of a target code to be read, and consequently to use the recording face effectively by reducing limitations imposed on the layout process. Moreover, the present invention also relates to a computer-readable memory medium which stores a program for allowing the computer to execute such a data recording method.
In the case when, from a recording medium 2 on which data is recorded as an optically-readable code 1 as illustrated in FIG. 1, the code is read by scanning it manually by using a reading device 3, it is necessary to solve problems resulting from the manual operation, such as instability in the scanning rate and inaccuracy in the reading position. For this reason, U.S. Pat. No. 5,866,895 has proposed a system in which digital data is divided into blocks, each block unit having a predetermined amount of information, and these are recorded on a recording medium, and reproduced. In the system disclosed by this U.S. Patent, each of the divided block data is read together with the corresponding address so that information is reproduced by combining the block data based upon the address. Since this system divides data on a block basis, and then records/reproduces the data, it is superior in that even in the manual scanning operation which has the problems of irregular scanning rates and inaccurate reading positions, it allows the data to be positively read.
Although this system, which divides data on a block basis, and then records/reproduces the data, provides great effects, consideration needs to be given to the following problems. In the event of a greatly winding scanning process due to the manual operation, since the entire blocks are not picked up correctly, a data loss might occur, or since images (hereinafter, referred to collectively as the peripheral image) such as a text (characters, symbols, etc.) 4 and a picture image (photographs, illustrations, etc.) 5, located on the periphery of the code, tend to be picked up together with the effective blocks, and these problems tend to cause serious adverse effects on the code reading operation.
For example, in the case of a reading operation on the code 1 recorded as shown in FIG. 2, the winding is only permitted up to WS, and any winding exceeding this limit causes the code 1 to deviate from a pickup area 6, resulting in a data loss.
Moreover, in the case when, as shown in FIG. 3, a block is constituted by data dots 7 corresponding to data to be recorded and a marker 8 that is an index of the block and that is also used for positioning the data dots 7 to be read, if there is a peripheral image similar to the marker at the pickup position A in FIG. 2, the resulting pickup screen 9 is like one as shown in FIG. 4; therefore, this peripheral image might be erroneously detected as the marker 8, resulting in a problem in the marker detecting process. Moreover, if there is a peripheral image having a reflectance higher than the highly reflective element of the code 1 or lower than the low reflective element of the code 1, the resulting pickup screen 9 is like one as shown in FIG. 5; therefore, the peak of luminance within the pickup screen, which forms a reference in the threshold process carried out upon judging the presence or absence of a dot, might be picked up from this peripheral image, resulting in a problem in the threshold detecting process.
Here, in order to solve the problem with the winding permissible limit, as illustrated in FIG. 6, a recording medium has been proposed in which data A to be recorded in a code 1 is duplicated so that a greater winding WSxe2x80x2 permissible limit is provided.
Moreover, in order to solve the problem with the peripheral image, one solution is to place the code 1 with a sufficient gap from the peripheral image. This arrangement makes it possible to prevent the block containing effective data from being picked up with the peripheral image, and consequently to prevent an inaccurate data reading process due to influences from the image.
However, this arrangement in which the code 1 is simply placed with a sufficient gap from the peripheral image so as to prevent the peripheral image from being picked up together with the code fails to effectively use the recording face. For example, recording only one code requires a large space on the periphery thereof, resulting in a reduction in the recording density and a limitation imposed on the layout of the recording face.
The present invention has been made so as to solve the above-mentioned problems, and it is an object to provide a data recording medium, as well as a data recording method, which allows a code to be read without being interrupted by interference from the peripheral image even when a reading device is not appropriately positioned on the code, and which also makes it possible to effectively use the recording face by reducing limitations imposed on the layout. Another object of the present invention is to provide a computer-readable memory medium which stores a program for allowing the computer to execute such a recording method.
According to a first aspect of the present invention, there is provided a data recording medium, comprising:
an area in which data is recorded as a code that can be optically read by a manual scanning process; and
a non-interference area placed on the periphery of the code, the non-interference area being an area from which any interference image having an attribute causing adverse effects in reading the code is not allowed to exist.
According to a second aspect of the present invention, there is provided a data recording method, which records data as a code that can be optically read by using a manual scanning process, comprising the steps of:
placing a non-interference area on the periphery of the code on the recording medium, the non-interference area being set so that any interference image having an attribute causing adverse effects on the code reading process is not allowed to exist therein; and
recording the code having the non-interference area.
According to a third aspect of the present invention, there is provided a computer-readable memory medium comprising a program containing instructions which, upon recording data as a code that can be optically read by using a manual scanning process, executes the steps of:
placing a non-interference area on the periphery of the code on the recording medium, the non-interference area being set so that any interference image having an attribute causing adverse effects on the code reading process is not allowed to exist therein; and
outputting the code including the non-interference area.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.